[RFC PATCH 4/4] PCI: meson: Remove redundant MPS configuration

[Niklas Cassel <cassel@kernel.org>]

From: Hans Zhang <18255117159@163.com>

The Meson PCIe controller driver manually configures maximum payload
size (MPS) through meson_set_max_payload, duplicating functionality now
centralized in the PCI core.  Deprecating redundant code simplifies the
driver and aligns it with the consolidated MPS management strategy,
improving long-term maintainability.

With meson_set_max_payload() gone, meson_size_to_payload() is only used
for MRRS.  Rename it to meson_size_to_mrrs(), update the warning message,
and drop the now-unused PCIE_CAP_MAX_PAYLOAD_SIZE and MAX_PAYLOAD_SIZE
macros.

Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Hans Zhang <18255117159@163.com>
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/pci/controller/dwc/pci-meson.c | 25 +++----------------------
 1 file changed, 3 insertions(+), 22 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-meson.c b/drivers/pci/controller/dwc/pci-meson.c
index 8559d132dcde..1d3687566dda 100644
--- a/drivers/pci/controller/dwc/pci-meson.c
+++ b/drivers/pci/controller/dwc/pci-meson.c
@@ -21,7 +21,6 @@
 
 #define to_meson_pcie(x) dev_get_drvdata((x)->dev)
 
-#define PCIE_CAP_MAX_PAYLOAD_SIZE(x)	((x) << 5)
 #define PCIE_CAP_MAX_READ_REQ_SIZE(x)	((x) << 12)
 
 /* PCIe specific config registers */
@@ -37,7 +36,6 @@
 #define PM_CURRENT_STATE(x)		(((x) >> 7) & 0x1)
 
 #define PORT_CLK_RATE			100000000UL
-#define MAX_PAYLOAD_SIZE		256
 #define MAX_READ_REQ_SIZE		256
 #define PCIE_RESET_DELAY		500
 #define PCIE_SHARED_RESET		1
@@ -256,7 +254,7 @@ static void meson_pcie_ltssm_enable(struct meson_pcie *mp)
 	meson_cfg_writel(mp, val, PCIE_CFG0);
 }
 
-static int meson_size_to_payload(struct meson_pcie *mp, int size)
+static int meson_size_to_mrrs(struct meson_pcie *mp, int size)
 {
 	struct device *dev = mp->pci.dev;
 
@@ -266,35 +264,19 @@ static int meson_size_to_payload(struct meson_pcie *mp, int size)
 	 * than 2^12, just set to default size 2^(1+7).
 	 */
 	if (!is_power_of_2(size) || size < 128 || size > 4096) {
-		dev_warn(dev, "payload size %d, set to default 256\n", size);
+		dev_warn(dev, "MRRS %d, set to default 256\n", size);
 		return 1;
 	}
 
 	return fls(size) - 8;
 }
 
-static void meson_set_max_payload(struct meson_pcie *mp, int size)
-{
-	struct dw_pcie *pci = &mp->pci;
-	u32 val;
-	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
-	int max_payload_size = meson_size_to_payload(mp, size);
-
-	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
-	val &= ~PCI_EXP_DEVCTL_PAYLOAD;
-	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
-
-	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
-	val |= PCIE_CAP_MAX_PAYLOAD_SIZE(max_payload_size);
-	dw_pcie_writel_dbi(pci, offset + PCI_EXP_DEVCTL, val);
-}
-
 static void meson_set_max_rd_req_size(struct meson_pcie *mp, int size)
 {
 	struct dw_pcie *pci = &mp->pci;
 	u32 val;
 	u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
-	int max_rd_req_size = meson_size_to_payload(mp, size);
+	int max_rd_req_size = meson_size_to_mrrs(mp, size);
 
 	val = dw_pcie_readl_dbi(pci, offset + PCI_EXP_DEVCTL);
 	val &= ~PCI_EXP_DEVCTL_READRQ;
@@ -363,7 +345,6 @@ static int meson_pcie_host_init(struct dw_pcie_rp *pp)
 
 	pp->bridge->ops = &meson_pci_ops;
 
-	meson_set_max_payload(mp, MAX_PAYLOAD_SIZE);
 	meson_set_max_rd_req_size(mp, MAX_READ_REQ_SIZE);
 
 	return 0;
-- 
2.55.0